The following relates generally to wireless communications, and more specifically to alternative modulation coding scheme (MCS) signaling.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform-spread-OFDM (DFT-S-OFDM). A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE). A base station may communicate with mobile devices (e.g., UEs) via downlink and uplink. The downlink (or forward link) may refer to the communication link from the base station to a UE, and the uplink (or reverse link) may refer to the communication link from the UE to the base station.
During communications, wireless devices (e.g., base stations, UEs, etc.) may employ different modulation coding schemes (MCSs) (e.g., different implementations of modulation schemes, coding rates, transport block sizes (TBSs), spatial streams, etc.) to address different system needs. For example, higher coding rates may be associated with increased data throughput, but may be more sensitive to interference and multi-path issues, while lower coding rates may provide for more robust communications, but may be associated with lower data rates. In some examples, base stations and UEs may access an MCS table to determine the MCS to use for an uplink or downlink transmission. However, wireless communications systems may also support additional MCSs, and standard or default MCS tables may not include data entries (e.g., MCS values) that account for these alternative MCSs that may be supported by the communications system. Improved techniques for determination and indication of these alternative MCSs (e.g., MCS values not included in a default table) may thus be desired.